def datasets():
ns = [TreeNode(i) for i in [8, 6, 10, 5, 7, 9, 11]]
ns[0].left, ns[0].right = ns[1], ns[2]
ns[1].left, ns[1].right = ns[3], ns[4]
ns[4].left, ns[4].right = ns[5], ns[6]
ns_r = [TreeNode(i) for i in [8, 6, 10, 5, 7, 9, 11]]
ns_r[0].right, ns_r[0].left = ns_r[1], ns_r[2]
ns_r[1].right, ns_r[1].left = ns_r[3], ns_r[4]
ns_r[4].right, ns_r[4].left = ns_r[5], ns_r[6]
return ns, ns_r
def construct_helper(pre_order, in_order, pre_start, pre_end, in_start,
in_end):
if pre_start > pre_end:
return
index = -1
for (i, num) in enumerate(in_order):
if num == pre_order[pre_start]:
index = i
break
if index == -1:
raise RuntimeError(u"错误的输入")
root = TreeNode(pre_order[index])
left_length = index - in_start
root.left = construct_helper(pre_order, in_order, pre_start + 1,
pre_start + left_length, in_start, index - 1)
root.right = construct_helper(pre_order, in_order,
pre_start + left_length + 1, pre_end,
index + 1, in_end)
return root
right = get_depth_of_tree(root.right)
return left + 1 if left > right else right + 1
def is_balanced_tree(root):
if not root:
return True, 0
left, left_depth = is_balanced_tree(root.left)
right, right_depth = is_balanced_tree(root.right)
return left and right and abs(
left_depth - right_depth) <= 1, \
left_depth + 1 if left_depth > right_depth else right_depth + 1
if __name__ == '__main__':
node1 = TreeNode(1)
node2 = TreeNode(2)
node3 = TreeNode(3)
node4 = TreeNode(4)
node5 = TreeNode(5)
node6 = TreeNode(6)
node7 = TreeNode(7)
node1.left = node2
node1.right = node3
node2.left = node4
node2.right = node5
node3.left = node6
node3.right = node7
print get_depth_of_tree(node1)
print is_balanced_tree(node1)
def helper(root, n, val, nodes):
val += root.val
nodes.append(root)
if not root.left and not root.right:
if val == n:
for node in nodes:
print node.val,
print "\n"
nodes.pop()
return
if root.left:
helper(root.left, n, val, nodes)
if root.right:
helper(root.right, n, val, nodes)
nodes.pop()
if __name__ == '__main__':
node1 = TreeNode(10)
node2 = TreeNode(5)
node3 = TreeNode(12)
node4 = TreeNode(4)
node5 = TreeNode(7)
node6 = TreeNode(6)
node7 = TreeNode(7)
node1.left = node2
node1.right = node3
node2.left = node4
node2.right = node5
print_path_of_n(node1, 22)
def datasets():
ns = [TreeNode(i) for i in [8, 8, 7, 9, 2, 4, 7]]
ns[0].left, ns[0].right = ns[1], ns[2]
ns[1].left, ns[1].right = ns[3], ns[4]
ns[4].left, ns[4].right = ns[5], ns[6]
return ns